Protecting Document Libraries from Malicious Use

Assuming that antivirus software has been installed, the following are the steps for activating the product:

1.	From SharePoint Central Administration, scroll down to Security Configuration.
2.	Click on Configure Antivirus Settings.
3.	The Scan Documents on Download and the Scan Documents on Upload boxes should be selected.
4.	Select the Attempt to Clean Infected Documents box to attempt cleaning infected files.
5.	If users will be saving files locally that may be infected, there is an option to Allow Users to Download Infected Documents. However, it is not recommended to use this option.
6.	To have the scanning process time-out after a specified amount of time, enter the time (in seconds) in the Time Out Scanning After ___ Seconds box. The default time is 300 seconds, which is equivalent to 5 minutes.
7.	Type the number of threads to use during the scanning process in the Allow Scanner to Use Up to ___ Threads box. The default is five, which should handle most sites.
8.	Click OK to save the entries.

As another protective mechanism, Windows SharePoint Services enables blocking undesirable file types from being uploaded or accessed, based on the file's extension. Several file extensions are blocked by default, including any file that has an extension that Windows Explorer treats as an executable. The list of extensions being blocked is maintained for the entire server farm in the configuration database. To add to the list, follow these steps:

1.	From SharePoint Central Administration, scroll down to Security Configuration.
2.	Click on Manage Blocked File Types. The file types currently blocked are displayed.
3.	Add or remove file types as necessary by typing in each file extension on a separate line.
4.	Click OK when finished.